Planting apparatus such as planters and drills are used for planting seed in agricultural fields. Planters and drills are typically implements having row units for applying seed to the field as the implement is pulled by a vehicle such as an agricultural tractor. Typically, planters meter individual seeds while drills plant a mass or volume of seed. The metering and placement accuracy is typically higher for planters than for drills. Thus, seeds of crops (e.g., corn) which require relatively high metering and placement accuracies for efficient growth are typically planted using planters, while seeds of crops (e.g., wheat; oats) which grow efficiently in more varied seed environments are planted by lower accuracy and less expensive drills. Despite the differences, both types of planting apparatus typically include a seed hopper for storing a single type of seed to be planted.
Many types of planters and drills are known and are illustrated by the product lines made by Case Corp. of Wisconsin, the assignee of the present invention. For example, 955 Series EARLY RISER CYCLO AIR.RTM. Planters are a family of planters including central-fill seed hoppers for storing seed, pressurized air metering systems for metering seed and air distribution systems for delivering the metered seed to row units. Planter models in this family can plant different numbers of rows at different row widths. Case Corp. also makes the 900 Series EARLY RISER Plate Planter family which includes a variety of plate planter models. Drills made by Case Corp. include the 5300, 5400, 5500, 7100 and 7200 drills which include different numbers of openers, opener spacings and seeding widths. The above-described planters and drills are used to apply a single type of seed stored in a seed hopper.
Conventional agricultural practices have treated fields as having uniform parameters. However, research has shown that crop production may be optimized by taking into account spatial variations that often exist within a given farming field. For example, by varying the farming inputs applied to a field according to local conditions within the field, crop yield as a function of the inputs being applied can be optimized while environmental damage is prevented or minimized. Farming inputs which have been applied according to local field conditions include herbicides, insecticides, and fertilizers. The practice of farming according to local field conditions is known as precision, site-specific or prescription farming.
Prescription farming, however, has not adequately managed the type of seed which is applied to a field. As explained above, conventional planting apparatus applies a single type of seed uniformly throughout a field. This practice does not account for site-specific variations throughout a field that affect the seed environment and the efficiency of different types of seed. Site-specific parameters which affect the seed environment include soil type, nutrient levels, field slope, weed pressure, insect pressure, and past yield history. Because variations in these parameters throughout a field have varying affects on different types of seed, results obtained when a field is planted using a conventional planting apparatus which plants a single type of seed have been less than optimal.
A situation in which the optimal seed type depends upon site-specific parameters includes the use of seeds genetically engineered for increased insect resistance. Advantages of such seeds can be offset by disadvantages such as increased cost and decreased yield. Efficiency may therefore be optimized by planting such seeds only in areas of a field which are infested by insects with other areas planted with conventional seed. However, switching between these seed types using conventional planters and drills has been difficult and inconvenient. Other situations in which the use of multiple types of seed in a field could increase productivity are known to farmers.
Accordingly, it would be advantageous to provide a system for dispensing multiple types of seed throughout an agricultural field. The multiple types of seed can include seeds of different crops, or seeds of different varieties of the same crop. It would be advantageous to provide a system for dispensing multiple types of seed according to a predetermined geo-referenced prescription type map. Further, it would be advantageous to provide a system for dispensing multiple types of seed at variable rates according to prescription type and rate maps. It would also be advantageous to provide controls allowing for manual override of the prescription type or rate. It would further be advantageous to provide a system for dispensing multiple types of seed which requires only minimal modifications to existing planting apparatus.